Water-base paints have become very popular in recent years as a result of their ease of brush application and, of course, the tremendous advantages permitted by water-cleanup. Brushes can very easily be rinsed in water and the cleanup water can usually be disposed of in the local sewer system. Water-base paint formulations have been devised to dry rapidly with very little odor and to be water-resistant when dry. However, in spite of these advantages, heretofore there have been sufficient disadvantages in certain areas of application as to continue to require the use of oil-base paint. Thus, while there have been water-base paint formulations devised to yield somewhat of a semi-gloss coating, a full gloss coating has only been commercially achievable with paint having an oil base. Of equal significance is the fact that water-base paint cannot be satisfactorily dispensed in aerosol form. Accordingly, when both high-gloss and flat coatings are to be applied, the painter must use two systems of cleanup or else not use water-base paint. Applications requiring the efficiencies of spray painting have been necessarly limited to the use of oil-base paint with their consequent environmental disadvantages. In this regard, oil base paints used in aerosol spray cans often employ solvents which have in recent years been recognized as imposing severe environmental hazards, which solvents are increasingly being classified as "restricted" in air pollution control regulations. Additionally, certain of such solvents are now known to be hallucinogens, and are therefore health hazards. Additionally, water-base paints have to be carefully formulated to avoid can corrosion and stability problems.
The present invention eliminates the foregoing disadvantages by providing a paint formulation which can be dispensed in aerosol form, but which is water-receptive and which can be readily cleaned up with water. Formulations can be provided in accordance with this invention to obtain coatings ranging from flat to high gloss. Specifically, the formulations contain no water, or only minimal amounts of water, thereby eliminating can corrosion and stability problems, and permitting spraying from an aerosol can, yet the paint when applied can be cleaned up with water. After drying, the resultant coating is quite water resistant. Importantly, the foregoing environmental and health hazards are completely eliminated.
In particular, a paint composition is provided comprising a water-soluble, neutralized resin film former in a water-soluble solvent therefor. The film former is obtained by reaction of a resin containing carboxyl groups with an amine or ammonia as a basic neutralizer to form a salt. The resin contains sufficient carboxyl groups to be solubilized by the neutralizer as hereinafter described in more detail. Suitable resins for neutralizations are maleinized oils, oil modified alkyds, copolymer alkyds, oil-free alkyds, acrylic solutions, copolymer oils containing carboxyl groups, urethane polymers and epoxy esters. Significantly, the paint composition is formulated with no water or with only a minimal amount of water, more specifically with a maximum content of 8 weight percent. Pigment can be added to provide any desired color and in an amount sufficient to provide hiding power. Wetting agents and anti-settling agents can be used in conjunction with pigments to help disperse the pigments and maintain them in a dispersed state. Dryers can be added to accelerate oxidation of the coating to facilitate drying and slip additives can be added so to impart mar resistance to the dried coating. Anti-rust inhibitors can be added as desired as can perfumes. The formulations are characterized by a high gloss, but a flattening agent, such as silica, can be incorporated to provide a flat coating.
The paint formulations can be applied with a brush, but find their greatest advantage in being dispensed in aerosol form. In this regard, the usual aerosol-type system comprises a pressure-tight spray can having a valved opening and containing a liquid paint composition and a volatile propellant for spraying the liquid composition through the valve opening. The present invention improves upon that system by providing the above water-receptive paint formulation.